The firing of a firearm is typically controlled by a trigger mechanism. The trigger mechanism includes a trigger that, when pulled, releases spring-loaded components that initiate the firing sequence. In fully automatic firearms, the trigger mechanism is generally placeable in a safety mode in which the trigger mechanism cannot be operated, a semi-automatic fire mode in which the trigger mechanism can be operated to fire a single round with each pull of the trigger, and an automatic mode in which the trigger mechanism can be operated to fire a plurality of rounds while the trigger is maintained in the pulled position. In some instances a handle or lever is provided to place the firearm in the various modes. In such cases, the firearm will remain in whichever position the operator places the handle or lever until the operator moves the handle or lever to another position. This type of configuration can result in an operator being unaware of the operating mode of the firearm. For example, the operator may fire the firearm in the automatic mode while believing the firearm to be in the fire mode.